Non-heme iron containing oxygenases have been shown to be involved in a large number of metabolic processes in both mammalian and bacterial systems. The goal of this research program is to probe the involvement of non-heme iron in the catalytic pathway of a selected oxygenase. Particular attention will be paid to the possibility of changes in coordination geometry during catalysis, to the relationship between substrate binding site and the metal ion, to the factors which influence substrate binding and to the possible role of protein functional groups in catalysis. Of particular significance, highly potent active site directed substrate analogs have been developed, and further work will be aimed at refining the structure of such ligands.